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# Target definition file fragment for ethernet devices.

#

# The target-side can instantiate up to four ethernet devices,

# eth0 to eth3. Each instance requires an entry in the

# target definition file specifying what underlying Linux

# kernel facility should be used to implement the I/O. This

# can take the following forms:

#

# 1) an existing ethernet device, e.g.

#        eth0 real eth1

#    thus mapping the eCos device eth0 on to the Linux device eth1.

#    The latter network interface must not currently be in use

#    by Linux. Traffic will flow to and from the real ethernet, and

#    communication is possible with any machine on the LAN.

#

# 2) the Linux kernel's tap facility.

#        eth0 ethertap

#    This will result in a Linux ethernet interface such as

#    tap3 appearing. The interface can be configured like any

#    other network device, for example by using the ifconfig

#    command or by creating a configuration file

#    /etc/sysconfig/network-scripts/ifcfg-tap3

#    The result is a virtual ethernet segment visible only

#    to the Linux host and eCos. Bridge software inside the

#    Linux host can be used to connect eCos to a larger network.

#

#    Optionally a specific tap device can be configured,

#        eth0 ethertap tap3

#    By default the code will pick up the next free tap device,

#    usually tap0. If the Linux interface should come up automatically

#    then this can be achieved with an ifcfg-tap?? configuration

#    file. Explicitly specifying the tap device can avoid some

#    confusion.

#

#    Both the eCos and the Linux network interface need a unique

#    MAC address. There is no real ethernet hardware involved to

#    supply these addresses, so they have to be invented. The

#    Linux kernel will automatically invent one for its interface.

#    By default a random MAC address will also be generated for

#    the eCos interface, but to make the system more deterministic

#    it is possible to specify the MAC address to be used. This

#    facility is only available in conjunction with an explicit

#    tap device, e.g.:

#        eth0 ethertap tap3 00:01:02:03:04:05

#    The MAC address should be in the usual format: six 2-digit

#    hexadecimal numbers separated by colons. It is the user's

#    responsibility to make sure that the address specified

#    does not match any other real or invented address visible

#    on the local network.

#

# It is possible that bursts of ethernet traffic occur, causing

# packets to arrive faster than they can be forwarded to and

# processed by eCos. It is desirable that some number of packets

# be buffered, matching the behaviour of many ethernet devices

# with built-in fifos. However the number of these packets should

# be restricted: if eCos stops accepting ethernet packets or

# cannot handle the data quickly enough, then it is possible that

# an unlimited number of packets could accumulate in the I/O

# auxiliary until all available memory and swap space is exhausted.

# By default up to 16 packets will be buffered per device, but

# this can be changes with the max_buffer option.

#

# The ethernet emulation code can perform logging and limited

# analysis of each ethernet packet. For example if a particular

# packet is an IPv4 ICMP request then details of the request

# will be logged to the main text window. The appearance of the

# various filters can be controlled here, using the usual

# options such as -foreground, -background, and -hide.

#

# This logging of each ethernet frame can be somewhat time-consuming

# and, for a long run, require a lot of memory. Logging can be

# disabled by default if desired, and a button on the toolbar allows

# this setting to be toggled.

#

# Ethernet packets can be up to 1514 bytes, so showing entire packets

# on a single line can mean very wide lines. In practice the interesting

# data is usually at the start, so the output can be truncated to a

# maximum number of bytes. The data is displayed in hex so each byte

# requires two columns, and some spacing will be added as well to

# improve legibility.

synth_device ethernet {

    ## Map eCos devices on to Linux ones.

    # eth0 real eth1

    # eth0 ethertap

    # eth0 ethertap tap3

    eth0 ethertap tap3 00:FE:42:63:84:A5

    # eth1 ethertap tap4 00:FE:12:34:56:78

    # eth2 ethertap tap5 00:FE:9A:BC:DE:F0

    # eth3 real eth2

    ## Maximum number of packets that should be buffered per interface.

    ## Default 16

    max_buffer 32

    ## Should packets be logged? The default is yes.

    # logging  0

    ## Maximum number of data bytes to be shown.

    ## Default 64

    # max_show 128

    ## Filters for the various recognised protocols.

    ## By default all filters are visible and use standard colours.

    # filter ether     -hide 0

    # filter arp       -hide 1

    # filter ipv4      -hide 1

    # filter ipv6      -hide 1

    # filter icmpv4    -hide 1

    # filter icmpv6    -hide 1

    # filter udp       -hide 1

    # filter tcp       -hide 1

    # filter hexdata   -hide 0

    # filter asciidata -hide 0

}